// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_CWISE_UNARY_VIEW_H
#define EIGEN_CWISE_UNARY_VIEW_H

namespace Eigen {

namespace internal {
template<typename ViewOp, typename MatrixType>
struct traits<CwiseUnaryView<ViewOp, MatrixType>> : traits<MatrixType>
{
	typedef typename result_of<ViewOp(const typename traits<MatrixType>::Scalar&)>::type Scalar;
	typedef typename MatrixType::Nested MatrixTypeNested;
	typedef typename remove_all<MatrixTypeNested>::type _MatrixTypeNested;
	enum
	{
		FlagsLvalueBit = is_lvalue<MatrixType>::value ? LvalueBit : 0,
		Flags = traits<_MatrixTypeNested>::Flags &
				(RowMajorBit | FlagsLvalueBit |
				 DirectAccessBit), // FIXME DirectAccessBit should not be handled by expressions
		MatrixTypeInnerStride = inner_stride_at_compile_time<MatrixType>::ret,
		// need to cast the sizeof's from size_t to int explicitly, otherwise:
		// "error: no integral type can represent all of the enumerator values
		InnerStrideAtCompileTime =
			MatrixTypeInnerStride == Dynamic
				? int(Dynamic)
				: int(MatrixTypeInnerStride) * int(sizeof(typename traits<MatrixType>::Scalar) / sizeof(Scalar)),
		OuterStrideAtCompileTime = outer_stride_at_compile_time<MatrixType>::ret == Dynamic
									   ? int(Dynamic)
									   : outer_stride_at_compile_time<MatrixType>::ret *
											 int(sizeof(typename traits<MatrixType>::Scalar) / sizeof(Scalar))
	};
};
}

template<typename ViewOp, typename MatrixType, typename StorageKind>
class CwiseUnaryViewImpl;

/** \class CwiseUnaryView
 * \ingroup Core_Module
 *
 * \brief Generic lvalue expression of a coefficient-wise unary operator of a matrix or a vector
 *
 * \tparam ViewOp template functor implementing the view
 * \tparam MatrixType the type of the matrix we are applying the unary operator
 *
 * This class represents a lvalue expression of a generic unary view operator of a matrix or a vector.
 * It is the return type of real() and imag(), and most of the time this is the only way it is used.
 *
 * \sa MatrixBase::unaryViewExpr(const CustomUnaryOp &) const, class CwiseUnaryOp
 */
template<typename ViewOp, typename MatrixType>
class CwiseUnaryView : public CwiseUnaryViewImpl<ViewOp, MatrixType, typename internal::traits<MatrixType>::StorageKind>
{
  public:
	typedef
		typename CwiseUnaryViewImpl<ViewOp, MatrixType, typename internal::traits<MatrixType>::StorageKind>::Base Base;
	EIGEN_GENERIC_PUBLIC_INTERFACE(CwiseUnaryView)
	typedef typename internal::ref_selector<MatrixType>::non_const_type MatrixTypeNested;
	typedef typename internal::remove_all<MatrixType>::type NestedExpression;

	explicit EIGEN_DEVICE_FUNC inline CwiseUnaryView(MatrixType& mat, const ViewOp& func = ViewOp())
		: m_matrix(mat)
		, m_functor(func)
	{
	}

	EIGEN_INHERIT_ASSIGNMENT_OPERATORS(CwiseUnaryView)

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR Index rows() const EIGEN_NOEXCEPT { return m_matrix.rows(); }
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR Index cols() const EIGEN_NOEXCEPT { return m_matrix.cols(); }

	/** \returns the functor representing unary operation */
	EIGEN_DEVICE_FUNC const ViewOp& functor() const { return m_functor; }

	/** \returns the nested expression */
	EIGEN_DEVICE_FUNC const typename internal::remove_all<MatrixTypeNested>::type& nestedExpression() const
	{
		return m_matrix;
	}

	/** \returns the nested expression */
	EIGEN_DEVICE_FUNC typename internal::remove_reference<MatrixTypeNested>::type& nestedExpression()
	{
		return m_matrix;
	}

  protected:
	MatrixTypeNested m_matrix;
	ViewOp m_functor;
};

// Generic API dispatcher
template<typename ViewOp, typename XprType, typename StorageKind>
class CwiseUnaryViewImpl : public internal::generic_xpr_base<CwiseUnaryView<ViewOp, XprType>>::type
{
  public:
	typedef typename internal::generic_xpr_base<CwiseUnaryView<ViewOp, XprType>>::type Base;
};

template<typename ViewOp, typename MatrixType>
class CwiseUnaryViewImpl<ViewOp, MatrixType, Dense>
	: public internal::dense_xpr_base<CwiseUnaryView<ViewOp, MatrixType>>::type
{
  public:
	typedef CwiseUnaryView<ViewOp, MatrixType> Derived;
	typedef typename internal::dense_xpr_base<CwiseUnaryView<ViewOp, MatrixType>>::type Base;

	EIGEN_DENSE_PUBLIC_INTERFACE(Derived)
	EIGEN_INHERIT_ASSIGNMENT_OPERATORS(CwiseUnaryViewImpl)

	EIGEN_DEVICE_FUNC inline Scalar* data() { return &(this->coeffRef(0)); }
	EIGEN_DEVICE_FUNC inline const Scalar* data() const { return &(this->coeff(0)); }

	EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR inline Index innerStride() const
	{
		return derived().nestedExpression().innerStride() * sizeof(typename internal::traits<MatrixType>::Scalar) /
			   sizeof(Scalar);
	}

	EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR inline Index outerStride() const
	{
		return derived().nestedExpression().outerStride() * sizeof(typename internal::traits<MatrixType>::Scalar) /
			   sizeof(Scalar);
	}

  protected:
	EIGEN_DEFAULT_EMPTY_CONSTRUCTOR_AND_DESTRUCTOR(CwiseUnaryViewImpl)
};

} // end namespace Eigen

#endif // EIGEN_CWISE_UNARY_VIEW_H
